Dongguan Ludi Automobile Technology Co., Ltd , https://www.ludirefitted.com
1 Introduction
Xiaosigou located in Pingquan County, Hebei Province, Hebei former copper mine. Since January 1, 1986 under the China Nonferrous Metal Industry Corporation.
Built in 1970, the 200t/d copper selection plant was completed in 1971. It was expanded in July 1975, and a 3000t/d copper plant was built in September 1979. Renovated in 1980, it was converted into a 1500t/d molybdenum series in March 1980. In May 1985, the second series was successfully rebuilt. Now, there are two molybdenum series production, processing ore capacity of 3000t / d. In recent years, the amount of molybdenum concentrate produced was 768 tons in 1986 and 808 tons in 1987.
2. Deposits, ores and mining
The Xiaosigou deposit is located at the border of the northern margin of the eastern part of the Yanshan area and the southern margin of the Inner Mongolian axis. It is a porphyry-skarn type large copper-molybdenum deposit. The deposit consists of molybdenum ore bodies and copper ore bodies, and their spatial distribution and occurrence characteristics are significantly different.
Molybdenum ore body: fine vein disseminated porphyry molybdenum ore. It is produced in the bed with contact with granite porphyry and granodiorite porphyry. It is lenticular and layered. The length along the strike is 1000~1400m, the thickness is 5~150m, and the slope is 100~450m. The upper part of the main ore body is thick and complete, and it is divided into a funnel shape. The average grade of molybdenum in the ore body is 0.075%~0.167%, and the associated copper grade is 0.077%~0.136%.
The ore is composed of quartz fine vein penetrating granite porphyry containing molybdenum ore and granodiorite porphyry. Metal-based minerals molybdenite, pyrite, chalcopyrite followed. Gangue minerals are quartz, feldspar, sericite, muscovite, chlorite and the like.
Copper ore body: mainly skarn type copper deposit, rarely in porphyry. It is vein-like, layer-like, and lenticular. Serpentine, chlorite, and skarnization of dolomitic limestone distributed in the contact zone of rock mass. The ore body is 120~700m long, 4~50m thick, and the slope is 100~370m. The ore grade is 0.91%~0.98%Cu, 0.009%~0.039% Mo. Most of the molybdenum in the ore is in a sulfided state (0.07% of full Mo grade, 0.068% of sulfide grade, and 0.002% of oxidation grade).
Xiaosigou uses a pit mining process.
3. Mineral processing technology
The Xiaosigou selection plant uses a three-stage, closed-circuit crushing process. The ore is fed into the ¢700/130mm rotary crusher through a 1.8×2.0m plate type feeding machine . The medium crushing machine adopts a ¢2200mm standard cone crusher , and the fine crushing adopts two ¢2200mm short-head cone crushers and two 1.8×3.6m. The vibrating screen is closed. The mesh hole is 15mm.
The copper-molybdenum mixed flotation is divided into two parallel series, coarse grinding, one rough selection, one sweep selection, and three selection processes. Each series consists of 2 sets of ¢2.7×3.6m ball mills and 2 sets of ¢2.4m double spiral classifiers to form a rough grinding, as shown in Figure 1. The graded overflow concentration is 36%~37%, and the fineness is 50%-200 mesh. The ball consumption is 1.8kg/t, and the processing capacity per series is 2000t/d.
Copper-molybdenum sorting process, see Figure 2. The second series of mixed concentrates are concentrated by a ¢1m thickener, and the bottom stream is ground to 801.5×3.0m balls to 80%～90%-360 mesh, then 8 times of selection, 1 sweeping, and the final molybdenum mine.
Copper beneficiation: Copper-molybdenum sorting tailings contain only 6%~10% of copper. After concentration, the underflow is further ground to 2.95%-360 mesh. After a coarse and fine sweep, the qualified copper concentrate is obtained.
Figure 1 Xiaosigou copper-molybdenum mixed flotation process
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Figure 2 Xiaosigou copper-molybdenum sorting process
4. Index of mineral processing
The ore grade: 0. 076% Mo, 0.20% Cu, grinding fineness 50% - 200 mesh.
Copper-molybdenum mixed concentrate grade: 4%~6%Mo, 6%~10%Cu, recovery rate 85%Mo, 55%Cu. The grinding degree is 80%~90%-360 mesh.
Molybdenum concentrate contains 47%~51% molybdenum and the selected molybdenum recovery rate is 93%~96%.
Copper concentrate contains 15% copper and the selected copper recovery rate is 95%.
Statistics of production indicators in recent years: In 1983, molybdenum concentrate contained 47.69% molybdenum and the molybdenum recovery rate was 77.68%. The copper concentrate contains 13.11% copper and the copper recovery rate is 49.21%. In 1984, molybdenum concentrate contained 48.33% molybdenum, molybdenum recovery rate was 78.33%, and molybdenum concentrate production was about 640t. In 1986, copper concentrate contained 14.4% copper, copper recovery rate was 51.38%, and molybdenum concentrate production was 768 tons.
In the thick and sweeping operation of the copper-molybdenum mixed flotation, Xiaosigou first adopted a large-scale CHF-14m 3 inflatable flotation machine. New equipment is effective in increasing recovery rates.
The molybdenum concentrate foam is dehydrated by ¢9m thickener and filtered by 3m 3 external filter filter. The filter cake is made of 21G-3 type 300×3000mm steam heating spiral dry machine. When the steam pressure reaches 0.4~0.6MPa, the treatment capacity reaches 400kg. /h, molybdenum concentrate water is less than 4%. This is lower cost and better than the original electric screw dryer.